A daisy creeps across a rocky landscape. It becomes a blade of grass, which, in turn, becomes a caterpillar, which then turns itself into a very miniature zebra. Nearby, a patch of clover says to the zebra, “Repetition is the only form of permanence I am capable of.”

This is a kind of everything.

This is David OReilly’s Everything, a game nestled somewhere between art piece and walking simulator, and perhaps best described by its title. It allows its player to be everything. This is also, however, a kind of cop out. Surely in trying to be everything, something is bound to be missed. It’s a loaded notion (indeed, when the game is ready to play, it declares, “EVERYTHING IS LOADED”), but it certainly tries. And it is better for it.

Take your pick from 3,000 playable characters in a collection of bespoke and procedurally generated landscapes, between which you are permitted to ascend and descend as you see fit. Perhaps you might like to be a flower. Perhaps you might like to be the moon. Perhaps you might like to be a cluster of stars. Perhaps you might, instead, like to know what a stone tower is thinking with the press of a button. Everything will tell you, and then it will collect the thoughts of things you encounter into a larger database of thoughts, which it will eventually use to generate thoughts of your own.

‘Everything persists, and everything is connected.’ Photograph: David Oreilly

The more you engage with, the more you know and you can gather ladybirds and boxwood trees Katamari Damacy-style across a meadow, soundtracked by lectures on the universe from philosopher Alan Watts while you do it. A boulder might remark to you that it hopes it remains springtime forever. It is certainly an experience.

In this way, Everything feels like a massively upscaled version of OReilly’s 2014 release, Mountain, which gave its players a procedurally generated mountain, contingent on little else.

Mountains might reflect on starlight, or show up with a dining room set poking out from its crags and hollows. Tech writer Leigh Alexander commented on Mountainback in 2014, saying, “It’s annoyingly simple … One of those things where you assume someone either ‘thinks they are so deep’ or is making fun of you. But listen: I love my mountain. I want to keep it.”

Everything takes this strange comfort of the procedurally generated personal to a universal scale, and it is good. It’s really good. Everything is a game that knows what its core strengths are, and it does not shy away from them: everything persists, and everything is connected.

Left to its own devices, Everything will do absurd things. Photograph: David Oreilly

Curiously, one of Everything’s best features is that the game will autoplay when left idle for more than a few seconds. One might let Everything play in the background while doing other things, letting it be an ambient aquarium of universes.

Left to its own devices, Everything will do absurd things. It will plop tubas into lakes, it will bring pieces of pizza the size of suns into space. The game becomes larger and larger, leaving flowers and moons behind to fold into earths, into ringed planets, into irregular galaxies, into planck lengths of the one-dimensional category, and then back into atoms. Or perhaps it will simply parade a group of multicoloured tents around a fire pit, and let that be that.

To some, this pleasure of letting a game play itself may come across as counterintuitive. But there is its own sort of pleasure in watching a thing create itself again and again, to know that the landscape either you or the game has created will never happen again.

This is your planck length of the one-dimensional category. It is no one else’s.

There are no people, no dialogue, no consequences. Photograph: David Oreilly

This persistence in spite of everything is Everything’s strength, but it is also to its detriment. It can begin to feel fairly lonely to exist in a universe which isn’t affected by your existence, or your changes.

You are an elephant in a collection of flat blocks, but to what end? You are a pile of volcanic rock the size of the Pyramids, and still the world carries on as if you were not. There are no people, no dialogue, no consequences for being a sea of caterpillars in an alien river. You are things and their thoughts, pieced together from their own exposure to the universe you exist in, ever recycling and generating into a potentially solipsistic infinity. Perhaps there is some comfort to find in this relentless existence, or perhaps it is merely depressing. But to be affected in this way – to contemplate one’s own relationship to the cyclical nature of things – isn’t necessarily a negative.

As you explore hills and alien climates as buttercups and trumpets, as aloe vera and as an Irregular 3D Structure, Alan Watts’s voice rumbles low and emphatic: “Billions of years ago, you were a big bang, but now you’re a complicated human being.” Perhaps this is enough.

PS4/Steam; £11.99; Pegi Rating 3+

The headline of this piece was updated on 27 March 2017 to remove a drug reference.